Public Folder Mailbox Import fails in Hybrid Configuration

When you run your Exchange Organization in hybrid mode with Office 365 and migrate your on-premises Public Folders to Office 365, you must configure a remote Public Folder Mailbox in the Exchange Organization settings.

Organization Configs with Exchange 2013 Public Folders On-Premise

With Public Folders on-premises, your Exchange Online Org looks like this:

Get-OrganizationConfig | fl *public*
DefaultPublicFolderAgeLimit             :
DefaultPublicFolderIssueWarningQuota    : 1.7 GB (1,825,361,920 bytes)
DefaultPublicFolderProhibitPostQuota    : 2 GB (2,147,483,648 bytes)
DefaultPublicFolderMaxItemSize          : Unlimited
DefaultPublicFolderDeletedItemRetention : 30.00:00:00
DefaultPublicFolderMovedItemRetention   : 7.00:00:00
PublicFoldersLockedForMigration         : False
PublicFolderMigrationComplete           : False
PublicFoldersEnabled                    : Remote
PublicComputersDetectionEnabled         : False
RootPublicFolderMailbox                 : 00000000-0000-0000-0000-000000000000
RemotePublicFolderMailboxes             : {PublicFolder-Mailbox001}

With Public Folders on-premises, your On-Premise Exchange Org looks like this:

Get-OrganizationConfig | fl *public*
DefaultPublicFolderAgeLimit             :
DefaultPublicFolderIssueWarningQuota    : Unlimited
DefaultPublicFolderProhibitPostQuota    : Unlimited
DefaultPublicFolderMaxItemSize          : Unlimited
DefaultPublicFolderDeletedItemRetention : 30.00:00:00
DefaultPublicFolderMovedItemRetention   : 7.00:00:00
PublicFoldersLockedForMigration         : True
PublicFolderMigrationComplete           : True
PublicFoldersEnabled                    : Local
PublicComputersDetectionEnabled         : False
RootPublicFolderMailbox                 : ae0ef819-90d2-45d0-92b6-8b2062cf71a3
RemotePublicFolderMailboxes             : {}

Organization Configs with Exchange 2013 Public Folders in Exchange Online

With Public Folders in Exchange Online, your Exchange Online Org looks like this:

Get-OrganizationConfig | fl *public*
DefaultPublicFolderAgeLimit             :
DefaultPublicFolderIssueWarningQuota    : 1.7 GB (1,825,361,920 bytes)
DefaultPublicFolderProhibitPostQuota    : 2 GB (2,147,483,648 bytes)
DefaultPublicFolderMaxItemSize          : Unlimited
DefaultPublicFolderDeletedItemRetention : 30.00:00:00
DefaultPublicFolderMovedItemRetention   : 7.00:00:00
PublicFoldersLockedForMigration         : False
PublicFolderMigrationComplete           : False
PublicFoldersEnabled                    : Local
PublicComputersDetectionEnabled         : False
RootPublicFolderMailbox                 : 5810bb30-cdda-4287-85a4-8a2547bb9b01
RemotePublicFolderMailboxes             : {}

With Public Folders in Exchange Online, your Exchange On-Premise Org looks like this:

Get-OrganizationConfig | fl *public*
DefaultPublicFolderAgeLimit             :
DefaultPublicFolderIssueWarningQuota    : Unlimited
DefaultPublicFolderProhibitPostQuota    : Unlimited
DefaultPublicFolderMaxItemSize          : Unlimited
DefaultPublicFolderDeletedItemRetention : 30.00:00:00
DefaultPublicFolderMovedItemRetention   : 7.00:00:00
PublicFoldersLockedForMigration         : True
PublicFolderMigrationComplete           : True
PublicFoldersEnabled                    : Remote
PublicComputersDetectionEnabled         : False
RootPublicFolderMailbox                 : 00000000-0000-0000-0000-000000000000
RemotePublicFolderMailboxes             : {mcsmemail.de/Users/PF365-Mailbox-01-55e3d544-ed5a-4557-9008-d8c1b6f06d86}

The remote public folder mailbox has been added to the on-premise Exchange configuration by using the following:

Set-OrganizationConfig -RemotePublicFolderMailboxes PF365-Mailbox-001 -PublicFoldersEnabled Remote

To be able to add the remote public folder mailbox in a hybrid configuration, you are required to add the public folder mailbox (or mailboxes if you have more than one serving the hierarchy) as a mail user.

Microsoft provides a PowerShell script as part of a script collection here.

The issue with Import-PublicFolderMailboxes.ps1

When you run the Import-PublicFolderMailboxes.ps1 script, you might run into the following error:

Cannot bind parameter 'Name' to the target. Exception setting "Name": "The length of the property is too long. Themaximum length is 64 and the length of the value provided is 65."    + CategoryInfo          : WriteError: (:) [New-MailUser], ParameterBindingException    + FullyQualifiedErrorId : ParameterBindingFailed,Microsoft.Exchange.Management.RecipientTasks.NewMailUser    + PSComputerName        : ex2013.mcsmemail.de

The name attribute for a mail user is limited to 64 characters. But why are you exceeding the length when the mailbox name is only 17 characters long?

It turns out that the PowerShell script adds a prefix name “” and the mailbox GUID as a suffix. And voilá, the name exceeds the allowed length for the mail user name attribute.

Recommendation

Don’t use more than 16 characters when naming the Public Folder mailboxes in Office 365.

Or modify the Import-PublicFolderMailboxes.ps1 script to fit your needs.

$hasPublicFolderServingHierarchy = $true;$displayName = $publicFolderMailbox.Name.ToString().Trim();# ORIG: $name = "RemotePfMbx-" + $displayName + "-" + [guid]::NewGuid();$name = $displayName + "-" + [guid]::NewGuid();$externalEmailAddress = $publicFolderMailbox.PrimarySmtpAddress.ToString();

Links

• Microsoft Exchange 2013 Public Folders Directory Sync Support Scripts

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You need assistance with your Exchange Server setup? You have questions about your Exchange Server infrastructure and going hybrid? You are interested in what Exchange Server 2016 has to offer for your environment?
Contact me at thomas@mcsmemail.de
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